“The plant security officers are willing to raise issues that could impact nuclear safety and nuclear security but they are reluctant to raise internal issues such as work hours, overtime, communications with management and worker fatigue,” Nuclear Regulatory Commission spokeswoman Prema Chandrathil said.

The plant created a plan to address the safety culture, but the NRC released a letter to the plant Friday that states the plant’s actions “have been insufficient to assess and understand the cause of the chilled work environment” among security workers and “did not demonstrate a strong commitment to effectively improve the safety conscious work environment.”

“Specifically, significant gaps were found to exist in the security officers’ knowledge of the actions being taken to address the chilled safety conscious work environment and management’s commitment to improving the overall safety conscious work environment,” the letter said.

Overall, Palisades' performance improved in 2013 according to regulators, but the plant near South Haven still had a few problems.

So far, 2014 has been relatively uneventful at Palisades. Workers fixed some longstanding issues that were causing a different leak from the vessel that contains the nuclear reactor. But during those repairs they also discovered a foreign object lodged in the vessel. Regulators don’t believe the object compromises plant safety.

Regulators will discuss these and other issues at a meeting on Thursday at 5 p.m. Meanwhile Entergy, the company that owns Palisades, will host an open house for the public on Tuesday from 5 p.m. to 7 p.m. Both meetings will take place at the Beach Haven Event Center in South Haven.